help with gs550

[arsprod]

GS gurus, I'm thrilled to find this forum! My son bought an 82 gs550l last Fall. I owned an 80 back in the day. It's been running OK but leaking fuel. I pulled the carbs last weekend and cleaned them up - actually looked OK. The bike is running again (much nicer actually) but still leaking fuel.

Tonight I discovered it's actually leaking around the left side cylinder head. To make things worse the bolt (underneath spark plug) snapped off - it was seriously rusted.

The weather is finally nice and the poor kid has no other transportation - and of course no money. Is he screwed, do we need to pull the head and replace the head gasket? Any advice is welcome, thanks!

Aaron in Indianapolis

 

[cowboyup3371]

Check your petcock for proper vacuum - it shouldn't allow fuel to flow in the on or reserve settings when the engine is off. PRI is for prime which allows fuel to flow without the vacuum - not something you want to use all the time.

 

[eil]

Show us some pictures. I'm not familiar with the '82 GS550, but from your description, it does rather sound like a new head gasket may be in order.

BassCliff will be along shortly with a big list of all the maintenance that needs to be done to your machine. I understand about being on a budget, but old bikes are only cheap to own and operate if all of the regular maintenance has been kept up over the years. Unfortunately, that's like 1% of all second-hand GSes and yours sounds like it probably falls in the other camp.

 

[arsprod]

I'm all too aware of the investment that old bikes take - my current project is an '82 Moto Guzzi, but it seems to have had a better life than this old Suzuki!

Here's a pic of the bike and a not so good closeup of the engine. The arrow is pointed at the bolt that broke.

 

[tom203]

As stated, check petcock operation; also check that petcock is not leaking at tank mount and dripping on head. It is gas that's leaking, right???

 

[arsprod]

As stated, check petcock operation; also check that petcock is not leaking at tank mount and dripping on head. It is gas that's leaking, right???

Yes, it's gas - I can see bubbling around the head gasket and there's spillage on the front of the engine

 

[AJ]

Doesn't look like a disaster to me.

Not entirely sure I understand the symptoms.

GS gurus, I'm thrilled to find this forum! My son bought an 82 gs550l last Fall. I owned an 80 back in the day. It's been running OK but leaking fuel. I pulled the carbs last weekend and cleaned them up - actually looked OK. The bike is running again (much nicer actually) but still leaking fuel.

Tonight I discovered it's actually leaking around the left side cylinder head. To make things worse the bolt (underneath spark plug) snapped off - it was seriously rusted.

Are you seeing "stains" around the number one cylinder?
Are they from gas or oil?
Did you break the bolt at the number one cylinder trying to tighten it because you thought it was leaking there?

Recommendations:
1) Determine if it's gas or oil you are seeing.
2) If it's gas, recommend checking that the petcock shuts off like it's supposed to (suggested by cowboy).
3) If it's gas, check the floats in the carbs. Very good chance that they are original and one or more of them is bad.
4) Do a compression test on all cylinders (cold engine). Do a leakdown test if you can, but a simple compression test is still helpful.

The broken bolt on the head is not a total disaster.

5) If the compression is low, then, yes, teardown, but it's an afternoon job most likely.
6) If the compression test is ok, you might be able to get the bolt out with a left hand drill and put in a new bolt. If not, it will probably start leaking there sooner or later, but it's still not a disaster. It's not one of the 6 major headbolts on this engine and you might be able to ride it just fine for a long time until it becomes bad and demands a new head gasket (and possible milling of the head if it warps).

 

[arsprod]

Doesn't look like a disaster to me.

Not entirely sure I understand the symptoms.

Are you seeing "stains" around the number one cylinder?
Are they from gas or oil?
Did you break the bolt at the number one cylinder trying to tighten it because you thought it was leaking there?

Recommendations:
1) Determine if it's gas or oil you are seeing.
2) If it's gas, recommend checking that the petcock shuts off like it's supposed to (suggested by cowboy).
3) If it's gas, check the floats in the carbs. Very good chance that they are original and one or more of them is bad.
4) Do a compression test on all cylinders (cold engine). Do a leakdown test if you can, but a simple compression test is still helpful.

The broken bolt on the head is not a total disaster.

5) If the compression is low, then, yes, teardown, but it's an afternoon job most likely.
6) If the compression test is ok, you might be able to get the bolt out with a left hand drill and put in a new bolt. If not, it will probably start leaking there sooner or later, but it's still not a disaster. It's not one of the 6 major headbolts on this engine and you might be able to ride it just fine for a long time until it becomes bad and demands a new head gasket (and possible milling of the head if it warps).

This is helpful, thanks. See my comments:

Are you seeing "stains" around the number one cylinder?
Are they from gas or oil? yes, and it's hard to tell. It may be gas that's mixed with dirt but I don't think it's oil
Did you break the bolt at the number one cylinder trying to tighten it because you thought it was leaking there? right - after engine heats up I'm seeing some bubbling right at the gasket line. It may be fuel that's dripping down from above but hard to tell

I'll do compression check and check float bowls (any suggestions for getting them off without taking the whole carb assembly out?).

Is there a retro kit for these petcocks to make them manual only?

 

[AJ]

This is helpful, thanks. See my comments:

Are you seeing "stains" around the number one cylinder?
Are they from gas or oil? yes, and it's hard to tell. It may be gas that's mixed with dirt but I don't think it's oil
Did you break the bolt at the number one cylinder trying to tighten it because you thought it was leaking there? right - after engine heats up I'm seeing some bubbling right at the gasket line. It may be fuel that's dripping down from above but hard to tell

I'll do compression check and check float bowls (any suggestions for getting them off without taking the whole carb assembly out?).

Is there a retro kit for these petcocks to make them manual only?

"bubbling right at the gasket line" does not sound good. Very likely a leak at the head gasket. Do a compression test. You may want to do it with both cold and hot engine. Pull all four spark plugs when you do the test and do it with the throttle held wide open.

Understand the difficulty telling between gas and oil, especially if the leak is very small. There's usually so much accumulated hydrocarbon goo left on these old engines that all of it will smell the same.

Testing the petcock is actually pretty easy. Pull the hoses off the petcock and install separate lines. Then suck on the small vacuum line and the fuel should flow out the big line and stop when you stop sucking. Easy test.

Even if your carbs were leaking, the fuel will either pour out the air filter side or the engine intake side, depending on how the carbs are oriented with respect to level. There really isn't a great path from the carbs up to the cylinder head from the outside.

I'm guessing you have a small leak at the head gasket and a compression test should show that. It is not a super hard job to fix, and not all that expensive either.

 

[arsprod]

Thanks AJ. The number 2 carb is definitely weeping and I read somewhere on BikeCliff's site that one symptom of petcock issues is extra fuel going to carb #2 (or I just think I remember that and I'm really making it up!). Anyhoo, I'll do the petcock test and guess it's time to go to Harbor Freight for compression tester - avoided buying one for years but guess it's for a good cause. More to come!

 

[Guest]

I just got done having petcock issues on son's 850G. Gas was flowing into #2 via the vacuum line and ruined a brand new oil change, wasted gas and lots of time. Used a clear hose to verify. Good luck!

 

[arsprod]

I just got done having petcock issues on son's 850G. Gas was flowing into #2 via the vacuum line and ruined a brand new oil change, wasted gas and lots of time. Used a clear hose to verify. Good luck!

I'm convinced that's exactly what's happening - ordered petcock rebuild kit and hoping to get it before the weekend.

 

[arsprod]

What's compression supposed to be on these motors? The manual I have says 140 something and I'm only getting 60-65, consistent on all cylinders (all plugs out).

 

[tom203]

What's compression supposed to be on these motors? The manual I have says 140 something and I'm only getting 60-65, consistent on all cylinders (all plugs out).

Make sure you or someone holds throttle wide open during compression testing cranking.
Be warned that petcock rebuild kits have poor success rate- but you likely can get brand new made in Japan petcock for under $50

 

[arsprod]

Make sure you or someone holds throttle wide open during compression testing cranking.
Be warned that petcock rebuild kits have poor success rate- but you likely can get brand new made in Japan petcock for under $50

Yeah, did that - but also realized I tested cold so will do again. Cheapest I found petcock replacement was $60. Figured I'd try the rebuild for $23 first!

 

[Suzuki_Don]

Yeah, did that - but also realized I tested cold so will do again. Cheapest I found petcock replacement was $60. Figured I'd try the rebuild for $23 first!

I am with Tom on this, don't waste your time and money on a rebuild, just buy a new petcock (genuine Suzuki). Another place you could check for a fuel leak if fuel is leaking onto the motor is the underneath side of the tank for a split seam or pin holes. I am not convinced it is a fuel leak, there should be a smell of petrol on the head if that was the case.

The compression test does not sound right either. One would expect the #1 cylinder to be lower than the other three. But they are all extremely low. Something not right there. Do the compression test again and record the readings. Then put a tea spoon of oil in each spark plug hole and immediately do the test again and report back on any differences in the readings.

 

[arsprod]

I am with Tom on this, don't waste your time and money on a rebuild, just buy a new petcock (genuine Suzuki). Another place you could check for a fuel leak if fuel is leaking onto the motor is the underneath side of the tank for a split seam or pin holes. I am not convinced it is a fuel leak, there should be a smell of petrol on the head if that was the case.

The compression test does not sound right either. One would expect the #1 cylinder to be lower than the other three. But they are all extremely low. Something not right there. Do the compression test again and record the readings. Then put a tea spoon of oil in each spark plug hole and immediately do the test again and report back on any differences in the readings.

Too late! Did the petcock rebuild and voila, no more leaking out of #2 carb. One additional piece of info - all the plugs looked perfect except #2 which was black and obviously been running rich. After the petcock rebuild I also did another once over on all the carbs and reinstalled. For the first few minutes the bike sputtered and popped, I'm assuming clearing out all the crap left in the #2 cylinder. It's now running nicely - idles better than ever.

However, there's still the issue of low compression. More to come. Thanks gents

 

[AJ]

60 psi is extremely low. Is your compression tester the type that screws into the plug hole, or the type with the rubber plug you press into the hole?

How many miles on this engine?

I think you've done something wrong with the test.

Also, wipe your finger inside the end of the exhaust pipe. If it is wet and oily, then you have a problem. But if it's mostly dry and powdery, then you might be ok.

 

[arsprod]

60 psi is extremely low. Is your compression tester the type that screws into the plug hole, or the type with the rubber plug you press into the hole?

How many miles on this engine?

I think you've done something wrong with the test.

Also, wipe your finger inside the end of the exhaust pipe. If it is wet and oily, then you have a problem. But if it's mostly dry and powdery, then you might be ok.

Screw in, 27k, powdery

 

[AJ]

Screw in, 27k, powdery

Screw in - good.

Powdery - very good. Indicated that your oil wiper rings are working, which usually means your compression rings are good.

27K miles - not terribly high. Your compression should be MUCH higher than that.

If you removed all four spark plugs first and held the throttle all the way open while cranking the engine, then I would suspect the gauge on the tester or the fittings on the gauge before tearing into this engine.

Do you have an air compressor with a gauge? You could connect your gauge to the compressor and compare the tester gauge to the one on your compressor.

I would definitely check the engine with a different gauge before tearing into this motor. Good luck!